1. Field of the Invention
The present invention concerns phase-separation equipment and a method for thermally separating an emulsion, in particular a water-oil emulsion, comprising a container to receive the emulsion, a heater to heat the emulsion in the container, a discharge to evacuate volatile emulsion constituents and also a condenser connected to the discharge to condense the vapor constituents.
2. Description of Related Technology
The operation of phase-separation equipment for the thermal separation of an emulsion is based on exploiting the different boiling points of the liquids forming the particular emulsion. Illustratively, oils boil up to about 300.degree. C. whereas water boils at about 100.degree. C. The thermal phase-separation technique makes use of this difference by heating the emulsion in the phase-separation container so that the liquid with the lower boiling point vaporizes and its vapor is evacuated at the surface of the emulsion. As regards to a water-oil emulsion specifically, the operating temperature, i.e. the emulsion temperature, is about 98.degree. C. Manifestly the operation of such equipment demands much energy. Attempts already have been undertaken to minimize energy losses when operating such equipment by insulating the container wall etc. However, the steps resorted to so far have been inadequate to assure a really significant lowering of energy consumption.
The object of the present innovation is to create phase-separation equipment of the above species which at increased output evinces a comparatively lower energy consumption.
This problem is solved for the phase-separation equipment of the above species by using an apparatus for introducing distributed air into the emulsion. It was found in a surprising manner and in particular with respect to the separation of a water-oil emulsion that by introducing the air in a two-dimensional manner into the heated emulsion, the formation of a water-vapor cloud occurs already at temperatures much below the boiling point of water. After equipment start-up, the separation of water therefore can take place at a substantially lower emulsion temperature and consequently less heat need be supplied. Again there is a reduction in energy demand in the condenser in that only smaller amounts of residual water vapor must be condensed. Another advantage of the innovation is that the condensate collection per hour is increased by about 100% compared to the state of the art. Hence the innovation amounts to a very significant step in an energy conservation and an increase in output when operating phase-separation equipment.
An appropriate design of the equipment of the invention is characterized in that a feedback means is provided which connects the discharge to the apparatus for the distributed air introduction. The cloud mixture of air and water-vapor evacuated from the surface of the emulsion is fed to the condenser and from there the residual air is fed back into the emulsion, whereby the advantage is achieved that the strongly odorous exhaust air -- which ordinarily passes from the condenser into the ambient -- remains in a closed system and therefore does not stress the environment. Furthermore the heat held in the evacuated air is not lost, rather it is returned to the system. Also, this step will not stress the air supply of the plant or building.
By inserting a high-pressure blower in the feedback means, the rate of air input to the emulsion is made high and accordingly the efficiency of phase separation is improved.
In another design of the equipment of the innovation, the apparatus for the distributed input of air is located near the bottom of the container. This arrangement leads to optimal efficiency by enabling the air bubbles to pass through the entire emulsion volume.
Another appropriate design of the equipment of the innovation evinces the feature that the apparatus implementing the distributed air supply consists of a two-dimensional pipe array comprising individual output apertures. This pipe array can be inserted into or suspended in the container as a unit so that already extant plants can be retrofitted.
As a result the energy consumption of extant plants can be substantially lowered by simple, economical capital expenditure.
Because the pipe array comprises individual, mutually parallel pipes which are cross-connected at their one ends so as to communicate with the feedback means while their other ends are outside the container, each being provided with a detachable closure means, the pipe array is optimally accessible from the outside. The pipe array can be cleaned in simple manner. There is no need to clean the pipe array from the inside of the container or to dismantle the pipe array for that purpose.
The nozzle-effect air introduction per se causes substantial mixing of the emulsion and thereby uniform heating of this emulsion. An agitator will appropriately increase the intensiveness of mixing.
In another appropriate design, a device controlling the heater temperature in relation to the particular emulsion temperature is provided. As a result the emulsion temperature after start-up can be kept constant when the nozzle-effect of the feedback air becomes noticeable.
The diameter of the output apertures appropriately is in the range of 6 to 12 mm.
Appropriately the apparatus for introducing the air i.e. the pipes, is made of stainless steel.